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Organic & Biomolecular Chemistry
1H), 7.33–7.40 (m, 4H) ppm; 13C NMR (100 MHz); δ −5.3 (q), trated under reduced pressure. The resulting crude product
−4.8 (q), 18.4 (s), 18.8 (q), 26.0 (q, 3C), 30.0 (t), 35.0 (t), 36.9 was used for the next step without purification.
(d), 39.9 (t), 63.2 (t), 74.5 (t), 76.0 (d), 80.2 (d), 81.2 (d), 114.4
The above crude mesylate (330 mg, 0.4 mmol) was dissolved
t
(t), 127.6 (d), 128.1 (d, 2C), 128.4 (d, 2C), 138.7 (s), 138.8 (d) in BuOH : H2O (10 mL, 1 : 1, v/v) and cooled to 0 °C in a cryo-
ppm; HRMS (ESI) m/z [M + H]+ calcd for C24H41O3Si 405.2819, stat and treated with methane sulphonamide (114 mg,
found 405.2828.
1.2 mmol) and AD-mix-α (800 mg, 2.0 g mmol−1). Stirring was
continued for 96 h at 0 °C. After complete consumption of the
starting compound as indicated by TLC, the reaction was
quenched with saturated sodium sulfite solution (5 mL) and
the reaction mixture was diluted with EtOAc (25 mL). The
organic layer was separated and the aqueous layer was
extracted with EtOAc (2 × 15 mL). The combined organic layer
washed with brine, dried (Na2SO4) and concentrated under
reduced pressure. The resulting crude product was purified by
silica gel column chromatography (15% EtOAc in petroleum
ether) to afford compounds 2 and 2′ in a diastereomeric
mixture (217 mg, 71% yield) as a colourless liquid. Rf = 0.4
(20% EtOAc in petroleum ether).
To the stirred solution of the diastereomeric mixture of
compounds 2 and 2′ (217 mg, 285 µmol) in dry dichloro-
methane (5 mL) were added triethylamine (0.2 mL,
1.43 mmol), acetic anhydride (81 µL, 855 µmol), and DMAP
(7 mg, 57 µmol) at 0 °C and stirred at room temperature for
6 h. The reaction mixture was concentrated and the residue
was dissolved in EtOAc (25 mL), washed with brine, dried
(Na2SO4) and concentrated under reduced pressure.
Purification of the crude product by silica gel chromato-
graphy gave compounds 2-Ac (180 mg, 79% yield) and 2′-Ac
(26 mg, 11% yield) as colourless liquids.
Compound 2-Ac. Rf = 0.3 (10% EtOAc in petroleum ether);
[α]2D5: −0.3 (c = 4.9, CHCl3); 1H NMR (400 MHz): δ 0.08 (s, 3H),
0.09 (s, 3H), 0.92 (s, 9H), 1.03 (d, J = 6.4 Hz, 1H), 1.05 (s, 9H),
1.35–1.43 (m, 1H), 1.51–1.75 (m, 10H), 1.80 (ddd, J = 5.1, 9.1,
14.1 Hz, 1H), 2.05–2.07 (m, 1H), 2.09 (s, 3H), 3.08 (t, J = 9.5
Hz, 1H), 3.15 (ddd, J = 1.6, 3.4, 9.3 Hz, 1H), 3.69 (td, J = 2.3,
5.8 Hz, 2H), 3.29–3.37 (m, 1H), 3.84 (dd, J = 1.6, 11.5 Hz, 1H),
3.70 (td, J = 2.5, 5.9 Hz, 2H), 3.90 (dd, J = 3.5, 11.6 Hz, 1H),
3.95 (ddd, J = 3.6, 5.8, 9.1 Hz, 1H), 4.13 (ddd, J = 5.9, 9.3, 11.8
Hz, 1H), 4.58 (d, J = 10.9 Hz, 1H), 4.71 (d, J = 10.9 Hz, 1H),
5.29 (t, J = 3.9 Hz, 1H), 7.29–7.45 (m, 11H), 7.67 (dd, J = 1.5,
7.8 Hz, 4H) ppm; 13C NMR (100 MHz): δ −5.3 (q), −4.8 (q),
18.4 (s), 18.7 (q), 19.2 (s), 21.1 (q), 25.4 (t), 26.0 (q, 3C), 26.9
(q, 3C), 29.1 (t), 32.1 (t), 32.3 (t), 36.9 (d), 39.3 (t), 39.9 (t), 63.2
(t), 63.8 (t), 74.5 (t), 75.5 (d), 76.4 (d), 76.9 (t), 80.1 (d, 2C),
81.3 (d), 127.6 (q, 4C), 127.6 (d), 128.1 (d, 2C), 128.4 (q, 2C),
129.5 (q, 2C), 134.0 (s, 2C), 135.6 (q, 4C), 138.7 (s), 17.05 (s)
ppm; HRMS (ESI) m/z [M + H]+ calcd for C47H71O7Si2
803.4733, found 803.4734.
Synthesis of 7-((tert-butyldiphenylsilyl)oxy)hept-1-en-4-ol (4)8b
Compound 4 was prepared following the literature procedure
reported by Shibuya and co-workers.8b
Rf = 0.3 (10% EtOAc in petroleum ether); [α]2D5: +4.1 (c = 2.2,
1
CHCl3); H NMR (400 MHz): δ 1.07 (s, 9H), 1.48–1.57 (m, 1H),
1.63–1.74 (m, 3H), 2.16 (br. s., 1H), 2.20 (ddt, J = 1.0, 6.5, 14.0
Hz, 1H), 2.30 (dddt, J = 1.1, 5.1, 6.5, 11.4 Hz, 1H), 3.65–3.69
(m, 1H), 3.71 (t, J = 6.0 Hz, 2H), 5.11–5.17 (m, 2H), 5.85 (ddt, J
= 7.0, 9.3, 16.8 Hz, 1H), 7.37–7.47 (m, 6H), 7.67–7.70 (m, 4H)
ppm; 13C NMR (100 MHz); δ 19.2 (s), 26.8 (q, 3C), 28.8 (t), 33.5
(t), 41.9 (t), 64.1 (t), 70.5 (d), 117.8 (t), 127.6 (d, 4C), 129.6 (d,
3C), 133.7 (s, 2C), 135.0 (d), 135.6 (d, 3C) ppm; HRMS (ESI) m/z
[M + H]+ calcd for C23H33O2Si 369.2244, found 369.2249.
Synthesis of compound 13 via cross metathesis of 3 with 4
Under argon, to a solution of compounds 3 (340 mg,
840 µmol) and 4 (929 mg, 2.52 mmol) in dry diethyl ether
(20 mL) were added sequentially CuI (16 mg, 84 µmol) and
Grubb’s 2nd generation catalyst (21 mg, 25.2 µmol) at room
temperature. The reaction mixture was kept at 40 °C for 36 h.
The solvent was evaporated under reduced pressure and the
crude product was purified by silica gel column chromato-
graphy (5% EtOAc in petroleum ether) to afford compound 13
(507 mg, 81% yield) as a colourless liquid. Rf = 0.3 (10% EtOAc
in petroleum ether); [α]2D5: +1.04 (c = 1.1, CHCl3); 1H NMR
(400 MHz); δ 0.09 (s, 3H), 0.10 (s, 3H), 0.93 (s, 9H), 1.02–1.05
(m, 3H), 1.06 (s, 9H), 1.44–1.55 (m, 2H), 1.60–1.72 (m, 7H),
2.07–2.25 (m, 5H), 3.08 (t, J = 9.5 Hz, 1H), 3.15 (ddd, J = 1.9,
3.5, 9.3 Hz, 1H), 3.28–3.39 (m, 1H), 3.61 (ddd, J = 4.1, 7.7, 11.9
Hz, 1H), 3.70 (d, J = 5.8 Hz, 2H), 3.83–3.93 (m, 2H), 4.59 (d, J =
10.9 Hz, 1H), 4.71 (d, J = 10.9 Hz, 1H), 5.44 (dt, J = 7.1, 15.1 Hz,
1H), 5.54 (dt, J = 6.6, 15.1 Hz, 1H), 7.29–7.45 (m, 10H),
7.65–7.70 (m, 5H) ppm; 13C NMR (100 MHz): δ −5.2 (q), −4.8
(q), 18.4 (s), 18.7(q), 19.2 (s), 26.0 (q, 3C), 26.8 (q, 3C), 28.8 (t),
28.9 (t), 33.4 (t), 35.5 (t), 36.9 (d), 39.9 (t), 40.7 (t), 63.2 (t), 64.1
(t), 70.8 (d), 74.5 (t), 76.0 (d), 80.2 (d), 81.2 (d), 126.1 (d), 127.6
(d, 5C), 128.1 (d, 2C), 128.4 (d, 2C), 129.6 (d, 2C), 133.8 (s),
134.0 (d), 134.2 (s) 135.6 (d, 4C), 138.7 (s) ppm; HRMS (ESI)
m/z [M + H]+ calcd for C45H69O5Si2 745.4678, found 745.4684.
Synthesis of disaccharide 2
Compound 2′-Ac. Rf = 0.3 (10% EtOAc in petroleum ether);
1
At 0 °C, a solution of compound 13 (300 mg, 0.4 mmol) and [α]2D5: −0.4 (c = 1.7, CHCl3); H NMR (400 MHz): δ 0.08 (s, 3H),
triethyl amine (0.17 mL, 1.21 mmol) in dry dichloromethane 0.09 (s, 3H), 0.92 (s, 9H), 1.04 (d, J = 6.4 Hz, 3H), 1.06 (s, 9H),
(10 mL) was treated with methane sulfonyl chloride (0.047 mL, 1.51–1.74 (m, 12H), 2.05 (s, 3H), 2.43 (dt, J = 7.1, 14.0 Hz, 1H),
0.6 mmol) and stirred at the same temperature for 1 h. The 3.09 (t, J = 9.5 Hz, 1H), 3.16 (ddd, J = 1.6, 3.3, 9.3 Hz, 1H),
reaction was quenched with water and the reaction mixture 3.30–3.40 (m, 1H), 3.70 (t, J = 5.8 Hz, 2H), 3.85 (dd, J = 1.4, 11.4
was diluted with dichloromethane (10 mL). The organic layer Hz, 1H), 3.91 (dd, J = 3.3, 11.5 Hz, 1H), 3.94–4.03 (m, 2H), 4.60
was separated, washed with brine, dried (Na2SO4) and concen- (d, J = 10.9 Hz, 1H), 4.71 (d, J = 10.9 Hz, 1H), 4.93 (dt, J = 3.3,
Org. Biomol. Chem.
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